Experimental Evaluation and Mechanism Analysis of Elastomer Failure Caused by Rapid Gas Decompression

Abstract

Gas dissolved in elastomer cannot release quickly and will expand dramatically when the pressure of surrounded gas environment suddenly released, resulting in gas bubble forming inside elastomer matrix and even rupture. The phenomenon is called rapid gas decompression (RGD) or explosive decompression (ED) failure. However, the research of gas especially acid gas effect on elastomer mainly focus on corrosion caused by chemical reaction. the RGD failure is mostly the result of physical action. In this study, the CO2 RGD resistant property of NBR elastomer material used in CO2 flooding downhole packer and PC pump was lab tested in accordance with operating condition. The failure critical point and appearance features were observed. And volume change behavior during pressurization, stabilization, decompression, and post decompression was also monitored. The elastomer RGD failure mechanism was analyzed. The research result provided solid foundation for service life prediction and selection of elastomer under high pressure and high CO2 gas content conditions.